Table 7. Second order rate constants (k_cat/K_m^sulfite) of active site mutants.

pH	Wild-type	Y343N	V474M	Y343F/R472Q	Y343N/R472M	Y343N/R472M/V474M
6.0	1.02 × 107	3330	1.30 × 106	2350	8.04	173
7.0	8.90 × 106	1.35 × 104	8.51 × 105	1970	24.4	237
8.0	5.95 × 106	4630	5.58 × 105	725	6.90	167
8.5	3.26 × 106	1990	4.46 × 105	316	3.30	27.9
9.0	1.16 × 106	632	1.36 × 105	69.2	1.32	10.1
9.5	3.92 × 105	86.6	5.36 × 104	12.4	0.47	4.71
10.0	2.46 × 105	36.5	3.08 × 104	4.96	ND*	0.67

^*Not Determined